The thermal performance of a power semiconductor device module depends on the material “stack” used for the module application. For example, in a common half-bridge power module (a typical module used in automotive applications), the transistors or semiconductor die are soldered to a substrate, which then can be soldered or fastened to a heat sink or base plate. In both cases, the stack-up of materials will generate high thermal resistance from the semiconductor junction to the heat sink.
The interface between the many layers of the stack-ups has the following drawbacks:
1. When the substrate is fastened to a heat sink, a thermal interface layer will need to be added to eliminate the air gap. This system normally has a high thermal resistance.
2. In case of soldering the substrate to a base plate, the system has a processing issue in that soldering a large substrate area to a base-plate can be difficult and can result in limited reliability of performance.
It is desirable to have a power module that does not exhibit the drawbacks of the prior art modules.